Expandable device for thermal therapy

ABSTRACT

A method and expandable device for thermally affecting tissue in which there is a fluid conduit. An expandable element includes a wall defining an inner volume. The wall has a tissue contact region which is non-coaxial with the longitudinal axis of the fluid conduit. The tissue contact region is operable to have a first contact surface area and a second contact surface area in which the second contact surface area is larger than the first contact surface area. A port is formed through the wall and is in fluid communication with the fluid conduit.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is related to and claims priority to U.S.Provisional Patent Application Serial No. 60/238,314, filed Oct. 5,2000, entitled SYSTEMS AND METHODS FOR CONTROLLING TEMPERATURE OF BRAINTISSUE, the entirety of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] n/a

FIELD OF THE INVENTION

[0003] The present invention relates to a device and method forcontrolling brain tissue temperature, and in particular, to a device andmethod for sub-cranial temperature control of brain tissue through theuse of expandable elements, such as balloons.

BACKGROUND OF THE INVENTION

[0004] The benefits of the application or removal of thermal energy toor from a localized portion of a tissue area to apply or remove thermalenergy is well known in the art. Balloons are commonly used to contact atissue. It is desirable to have a delivery device that facilitates theintroduction of thermal energy to a tissue region. While it is known touse balloons to contact tissue surfaces along the length of a catheterthat is inserted into a vessel, a need arises for a device to applylocalized thermal energy in alternate treatment scenarios. For example,as is known in the art, it is desirable to be able to apply or removethermal energy to or from the extreme end of a catheter.

[0005] It is also desirable to avoid creating unnatural openings in ahuman body. However, when a medical need mandates creating an opening,making as small an opening as possible is advantageous. The need to keepopenings to a minimum is particularly applicable when dealing withopenings in a human skull. However, a device is needed to apply orremove thermal energy to or from a tissue area with a larger surfacearea than the opening through which the catheter is inserted.

[0006] Problems of uniform thermal distribution also arise with knowndevices. When a thermally transmissive fluid is infused into a space,the distribution of thermal energy is governed by the function ofthermal convection. As such, in many situations thermal energy is notevenly distributed throughout the space. Therefore, it is desirable toprovide a device which evenly distributes or removes thermal energy fromtissue.

SUMMARY OF THE INVENTION

[0007] According to an aspect of the present invention, an expandabledevice for thermally affecting tissue is provided in which a fluidconduit having a longitudinal axis is in fluid communication with anexpandable element. The expandable element has a wall defining an innervolume. The wall has a tissue contact which is non-axial with thelongitudinal axis of the fluid conduit. The tissue contact region isoperable to have a first contact surface area and a second contactsurface area. The second contact surface area is larger than the firstcontact surface area.

[0008] According to another aspect of the present invention, anotherexpandable element for thermally affecting tissue is provided in which aport has a longitudinal axis and is in fluid communication with anexpandable element. A wall defines an inner volume and the wall has atissue contact region. The tissue contact region is non-coaxial with thelongitudinal axis of the port. The tissue contact region is operable tohave a first contact surface area and a second contact surface area. Thesecond contact surface area is larger than the first contact surfacearea.

[0009] According to yet another aspect of the present invention, amethod of using an expandable element to affect a thermal energy changein tissue of a patent's body is provided in which an opening is createdin the patient's body. The expandable element is in fluid communicationwith a fluid conduit and has a tissue contact region that is non-coaxialwith a longitudinal axis of the fluid conduit. The tissue contact regionis operable to have a first contact surface area and a second contactsurface area which is larger than the first contact surface area. Atleast a portion of the expandable element is inserted into the opening,having a first contact surface area, and into a region between an outerbarrier of the patent's body and the tissue. The tissue contact regionis then operated to the second contact surface area and infused with athermally transmissive fluid, thereby affecting a thermal change in thetissue.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

[0011]FIG. 1 is a perspective view of an exemplary embodiment of adevice constructed in accordance with the principles of the presentinvention;

[0012]FIG. 2 is a top view of an expandable element of the invention;

[0013]FIG. 3 illustrates a side view of the device shown in FIG. 1, in abundled state;

[0014]FIG. 4 is a side view of the device shown in FIG. 1, in a deployedstate;

[0015]FIG. 5 shows a perspective view of an alternate embodiment of anexpandable portion of the device constructed in accordance with theprinciples of the present invention;

[0016]FIG. 6 is a sectional view of the device taken along section 6-6in FIG. 1;

[0017]FIG. 7 is an alternate sectional view of the device taken alongsection 6-6 in FIG. 1;

[0018]FIG. 8 is another alternate sectional view of the device takenalong section 6-6 in FIG. 1;

[0019]FIG. 9 is still another alternate sectional view of the devicetaken along section 6-6 in FIG. 1;

[0020]FIG. 10 shows a cut-away perspective view of the device in adeployed state;

[0021]FIG. 11 is a planar view of a fluid distribution element of adevice constructed in accordance with the principles of the presentinvention;

[0022]FIG. 12 is an alternate planar view of a fluid distributionelement of a device constructed in accordance with the principles of thepresent invention;

[0023]FIG. 13 shows a cut-away end view of a device in a deployed stateconstructed in accordance with the principles of the present invention;

[0024]FIG. 14 is a sectional view of an exemplary interface region ofthe device taken along section 14-14 in FIG. 1;

[0025]FIG. 15 is a perspective view of a junction of a deviceconstructed in accordance with the principles of the present invention;

[0026]FIG. 16 is a cross-sectional view of an exemplary interface regionof the device taken along section 14-14 in FIG. 1;

[0027]FIG. 17 is a cut-away, perspective view of an alternatearrangement of a junction of a device constructed in accordance with theprinciples of the present invention;

[0028]FIG. 18 is a cut-away, perspective view of still another alternatearrangement of a junction of a device constructed in accordance with theprinciples of the present invention;

[0029]FIG. 19 is a sectional view taken along section 19-19 in FIG. 5;

[0030]FIG. 20 is a perspective view of an alternate embodiment of adevice constructed in accordance with the principles of the presentinvention;

[0031]FIG. 21 is a side view of an alternate fluid distribution elementof a device constructed in accordance with the principles of the presentinvention;

[0032]FIG. 22 is an overhead view of the fluid distribution elementshown in FIG. 21;

[0033]FIG. 23 is an bottom view of the fluid distribution element shownin FIG. 21;

[0034]FIG. 24 is a perspective view of an exemplary system in a bundledstate constructed in accordance with the principles of the presentinvention; and

[0035]FIG. 25 is a perspective view of an exemplary system in a deployedstate constructed in accordance with the principles of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0036] The present invention provides a device having an expandablesurface area for the application or removal of thermal energy to/from aselected site. The present invention also provides a device that can beinserted through an opening in a patient's body and expanded or deployedto cover a greater surface area than a device whose contact surface areais less than or equal to the size of the opening or which occupies thesurface area along a small portion of the length of the device. Furtherprovided is a feature which deploys the expandable portion of the deviceand supplies the expandable portion with material which imparts orremoves thermal energy from the selected tissue site.

[0037] Referring now to the drawing figures in which like referencedesignators refer to like elements, there is shown FIG. 1 a perspectiveview of an exemplary embodiment of a device constructed in accordancewith the principles of the present invention and designated generally asdevice 10. The device 10 includes a body 12 having a proximal end 14, adistal end 16 opposite the proximal end 14 and an expandable element 18such as a balloon coupled to the distal end 16 of the body 12. Theexpandable element 18 is provided with a physical structure that allowsthe expandable element 18 to be inserted through a small opening 20 andthen deployed, thereby expanding a tissue contact surface area 22. Whendeployed, the tissue contact surface area 22 has a surface area greaterthan when the expandable element 18 is not deployed, with which tocontact a tissue 24. Further, expandable element 18 is arranged to bedeployable within a region 25 between an outer barrier 27 and the tissue24 without causing damage to tissue 24. An example of region 25 is foundbetween the skull and the dura mater in a human. The tissue contactsurface area 22 can have a shape ranging from substantially flat toconcave or being flexible enough to conform to natural contours on thetissue surface.

[0038] In an alternate insertion procedure, the expandable element canbe placed against the dura mater which has been exposed by a craniotomy.An opening is then made in the boney plate, removed during thecraniotomy, for the body 12 of the device to pass through. When theboney plate is reattached to the skull, the expandable element remainswithin the epidural space, while the body 12 passes to the exterior ofthe skull. When removal of the expandable element is desired, theexpandable element can then be “deflated” and removed through theopening in the boney plate. Additionally, many different ways to reachthe boney material of a skull are contemplated. For example, the skinthat lies directly adjacent the location of the desired opening in theboney material can be cut or removed to allow the device to transversethe skin layer. Alternatively, an incision can be made a distance fromthe opening in the boney plate and the device “tunneled” under the skinto the skull insertion point.

[0039] In an exemplary embodiment of the invention, the expandableportion of the device is provided by a bundled expandable element 18.The bundled expandable element 18 defines a diameter small enough to fitinto a standard sized burr hole in a skull, such as 5 mm, 8 mm, 11 mmand 14 mm diameters. The expandable element 18 is then infused withchilled or heated fluid to expand its shape to a deployed state, theexpansion causing contact with the tissue to be treated. The fluid canthereby impart a thermal change to the expandable element which in turnimparts a thermal change to the contacted tissue. Furthermore, thetemperature of the fluid can be regulated such that a constanttemperature can be maintained or specific cooling/heating regimensprovided. The term fluid as used herein refers to a substance in aliquid state, a gaseous state, a transition state or a combinationthereof.

[0040] It is further contemplated that a device in accordance with theprinciples of the present invention can be used to create an epiduralpocket between the dura mater and the inner skull. For example, once thedevice is inserted into the opening and deployed, it will separate thedura from the inner skull, thereby creating an area for the device 10 toreside during a treatment. Alternatively, a discrete device or anattachment to the device 10 can be used to create the epidural pocketbefore deployment of the device 10. Further, it is contemplated that ahemostasis-inducing coating can be applied to the expandable element 18to reduce bleeding that can occur during operation of the device 10.Alternatively, the device 10 can be equipped with a method forcauterizing the dura as the epidural pocket is created, thereby reducingbleeding that may occur.

[0041]FIG. 1 shows the expandable element 18 in association with aflexible body 12, however, it will be readily understood by one ofordinary skill in the art that any number of alternate structures may beused, for example any-shaped expandable balloon element or multi-balloonelements having various sizes, shapes and diameters. Examples ofexpandable element 18 constructed in accordance with the principles ofthe present invention are described in greater detail below.

[0042]FIG. 2 is a top view of the expandable element 18. As shown inFIGS. 1 and 2, the expandable element 18 is in a deployed state.Further, FIG. 2 shows the expandable element having a substantiallycircular planar view, however, it will be readily understood that othershapes may be provided as well, for example, an oval shape, an amorphousshape, a spiral shape or a spider-like shape as discussed below.

[0043] The expandable element 18 has a wall 26 which defines an interiorvolume 28, shown in FIG. 2 in phantom cut-away. The wall 26 isconstructed of a resilient material that provides the ability to“deflate” or bundle the expandable element 18 into a bundled state, asshown in FIG. 3. Exemplary resilient materials include rubber, silicon,flexible and thermoplastic polymers.

[0044] Turning back to FIG. 2, the expandable element has a proximalside 30 which is opposite the tissue contact surface area 22 (not shownhere) which may contact the skull. Provided on the proximal side 30 is aport 32. The port 32 has a longitudinal axis extending through a centerof the port 32. FIG. 2 shows the port 32 positioned substantially in thecenter of the expandable element 18 on the proximal side 30. However, itwill be readily understood by those skilled in the art that port 32 canbe positioned in alternate locations, for example along the periphery ofwall 26.

[0045]FIG. 3 illustrates a side view of the expandable element 18 shownin FIG. 1 in a bundled state. FIG. 3 shows the expandable element 18having a bundled diameter d_(b) which preferably ranges in size up to 14mm.

[0046]FIG. 4 is a side view of the expandable element 18 shown in FIG. 1shown in the deployed state. In FIG. 4, the port 32 is providedsubstantially in the center of expandable element 18. However, it willbe readily understood that port 32 can be provided at alternatelocations on the expandable element 18. The port 32 provides a fluidcommunication pathway between the expandable element 18 and the body 12(not shown). The port 32 is also in fluid communication with theinterior volume 28 (not shown). As such, when the body 12 (not shown) isin fluid communication with the port 32, the body 12 is also in fluidcommunication with the interior volume 28. Alternate configurations of aconnection arrangement between the body 12, the port 32 and the interiorvolume 28 are discussed in further detail below. Expandable element 18has a deployed diameter “d_(d”) measured at the widest part along thewall and a height “h” measured from a top 34 of the expandable element18 to a bottom 36 of the expandable element 18. A circular expandableelement 18 constructed in accordance with the principles of the presentinvention can have a deployed diameter d_(d) ranging in size from 5 to200 mm. An exemplary embodiment has a deployed diameter d_(d) of 48 mm.Another exemplary embodiment has a deployed diameter d_(d) of 64 mm.Further, an exemplary embodiment can have a height h ranging in sizefrom 1 to 10 mm. In one exemplary embodiment the height h isapproximately 5 mm.

[0047]FIG. 5 shows a perspective view of an alternate embodiment of theexpandable element 18, shown as a shaped expandable element 38. Theshaped expandable element 38 has at least one expandable element arm 40which has a distal end 42 and a proximal end 44 opposite the distal end42, in which each expandable element arm 40 is joined at the proximalend 44 to a port 46 to create a “spider-like” expandable elementarrangement. Each expandable element arm 40 has a height “g” measuredfrom a top 48 of the expandable element arm 40 to a bottom 49 of theexpandable element arm 40. Further, each expandable element arm 40 has awidth “w” measured from a first side 50 of the expandable element arm 40to a second side 51 of the expandable element arm 40. Further, eachexpandable element arm 40 preferable has approximately a 2 to 1 width wto height g ratio. The materials used to construct the shaped expandableelement 38 include one or more of compliant, non-compliant, andpartially compliant polymers.

[0048] In use, deployment of the shaped expandable element 38 occurs aswith the above-described expandable element 18. Alternately, deploymentof a plurality of the expandable element arms 40 can occur individually.The ability to selectively deploy individual expandable element arms 40is provided by an individual injection member for each expandableelement arm 40 (injection members are more fully discussed below). Inpractice, an injection member that corresponds to an individualexpandable element arm 40 is provided with a flow of thermal fluid,which thereby inflates or deploys the corresponding expandable elementarm 40. The above described shaped expandable element can bemanufactured by standard polymer tube technology processes.

[0049]FIG. 6 is a sectional view of the body 12 taken along section 6-6in FIG. 1. The body 12 has a body wall 52 which defines at least onelumen. An inlet conduit 56 provides a conduit for the infusion of afluid into the expandable element 18. Further, an outlet conduit 60provides a conduit for removal of a fluid from the expandable element18. However, it is contemplated that the functions of the inlet conduit56 and the outlet conduit 60 can be reversed.

[0050] When the body 12 is connected to the expandable element 18, theinlet conduit 56 and the outlet conduit 60 are in fluid communicationwith the interior volume 28. As such, fluids can be introduced andevacuated from the interior volume 28 by way of the inlet conduit 56 andthe outlet conduit 60 of the body 12. Further, the body 12 can be acatheter which allows a user to position the expandable device 10 at atissue treatment site.

[0051]FIG. 7 is an alternate sectional view of the body 12 taken alongsection 6-6 in FIG. 1. FIG. 7 shows the inlet conduit 56 providedsubstantially coaxial with the longitudinal axis of the body 12.Further, the outlet conduit 60 is provided with a elongated shape alonga partial portion of the outer circumference of the inlet conduit 56.Additionally, a conduit 62 located along the outer circumference of theinlet conduit 56 and opposite the outlet conduit 60 is provided forcarrying accessory components, such as temperature and/or pressuresensor lead lines (not shown). It will be readily understood by oneskilled in the art that either the first or second lumen caninterchangeably act as an inlet conduit or an outlet conduit.

[0052]FIG. 8 is another alternate sectional view of the body 12 takenalong section 6-6 in FIG. 1. FIG. 8 shows the inlet conduit 56 centeredwithin the body wall 52 of the body 12 and two outlet conduits 60provided around a portion of the outer circumference of the inletconduit 56 within the body 12.

[0053]FIG. 9 is another alternate sectional view of the body 12 takenalong section 6-6 in FIG. 1. FIG. 9 shows a plurality of outlet conduits60 and a centrally located inlet conduit 56 provided around a portion ofthe outer circumference of the outlet conduit 60 within the body 12.Optionally, a conduit 62 can be provided to carry accessory componentsas discussed herein.

[0054] From these examples, it will readily understood that manyalternate arrangements can be made. For example, one or more accessoryconduits can be provided in any of the above disclosed configurations,the first and second lumens can act as either inlet or outlet conduitsand additional structures may be incorporated.

[0055]FIG. 10 shows a cut-away perspective view of the expandableportion of the device in a deployed state. Referring to FIG. 10,operation of this exemplary embodiment is discussed. In use, thethermally transmissive fluid is transferred into the interior volume 28through the inlet conduit 56 and evacuated from the interior volume 28through the outlet conduit 60. Circulation of the thermally transmissivefluid within the interior volume 28 transmits or removes thermal energyto or from the expandable element wall 26 by convection, whichcharacteristics are known to those skilled in the art. It iscontemplated that a steady thermal state can be maintained between thetreatment site and the expandable element 18 or that desirable thermalchanges can be affected.

[0056] Additionally, the present invention distributes the thermallytransmissive fluid in order to thermally control portions along thesurface of the device 10. It is contemplated that many different methodsof distributing the fluid can be used. Several exemplary fluiddistribution methods are described herein. One such method is providedby supplying a fluid distribution feature within the expandable element18, embodiments of which are discussed in more detail below.

[0057]FIG. 11 is a sectional planar view taken along section 11-11 inFIG. 1. FIG. 11 shows an interior surface 64 of the contact surface 22,which is disposed within the interior volume 28 of the expandableelement 18. Affixed to the interior surface 64 is at least one vane 66.It is contemplated that one or more vanes 66 can be used and that theirshape can be varied to advantageously affect fluid distribution withinthe interior volume 28 or to affect structural shape of the bundled ordeployed expandable element. For example, FIG. 11 shows four vanes 66extending radially from a center longitudinal axis to an outsideperiphery of the expandable element 18. The vanes 66 define flowpathways for the thermally transmissive fluid. The vanes 66 can be smallridges of protruding material or other such raised structures. As such,the vanes provide for even distribution of the thermally transmissivefluid within the interior volume 28, thereby reducing areas of uneventemperature. It will be readily understood by one of ordinary skill inthe art that different configurations can be employed to efficientlydistribute thermally transmissive fluid within the interior volume 28 ofthe expandable element 18 or to selectively distribute thethermally-transmissive fluid to specific portions of the interior volume28.

[0058]FIG. 12 shows another embodiment of a fluid distribution elementwith a greater number of vanes 66. FIG. 12 shows a plurality of“S”-shaped vanes 66 affixed to the interior surface 64 and extendingradially outward from a center longitudinal axis. It is contemplatedthat the vanes 66 are affixed to other surfaces in communication withthe interior volume 28. Further, the vanes 66 can be free-floatingwithin the interior volume 28.

[0059]FIG. 13, shows a cut-away end view of an expandable device in adeployed state constructed in accordance with the principles of thepresent invention. FIG. 13 shows the interior volume 28 having at leastone injection member 68 provided therein. FIG. 13 shows four suchinjection members 68. However, it will be readily understood thatvarious configurations may be provided.

[0060] Focusing on one injection member 68, the injection member 68 hasa proximal end 70 and a distal end 72. The proximal end 70 is in fluidcommunication with the inlet conduit 56 of the body 12 (not shown and asdescribed above). A junction 74 is provided to facilitate connection ofthe injection member 68 to the inlet conduit 56, however, otherarrangements without a junction 74 can also be employed, as discussedherein. Further, the distal end 72 defines an opening 76 for fluidoutput flow. Alternatively, an injection member 68 could have one ormore openings 76 along a length of the injection member 68, whether anopening at the distal end 72 is provided or not. Although all of theexemplary injection members 68 are shown in FIG. 13 as having equallengths, it is contemplated that each individual injection member 68 canhave the same or a length different from at least one other injectionmember 68. Additionally, the injection member 68 can be extruded from aurethane/pellethane material having a relatively soft durometer ormanufactured by other processes know in the art.

[0061] Referring to FIGS. 1 and 13 operation of the device is discussed,in use, thermally transmissive fluid is infused into the inlet conduit56 at the proximal end 14 of the body 12. The fluid then passes to thedistal end 16 of the body 12 and through the injection member 68, whichdirects the fluid to pre-specified locations within the interior volume28. In an exemplary embodiment the fluid is directed to a periphery 78of the expandable element 18. The thermally transmissive fluid therebyimparts or removes thermal energy from the tissue contact surface area22. The tissue contact surface area 22 can then affect a temperature ofthe tissue at a treatment site. The fluid is then evacuated from theinterior volume 28 via the outlet conduit 60 and returned to theproximal end 14 of the body 12 for recovery or reuse. This process canbe a continuous flow or can be regulated in cycles or steps.

[0062] As such, the thermally transmissive fluid is directed to apre-selected area of the interior volume 28 to provide for a reductionin the occurrence of uneven temperature areas within the interior volume28. Further, it is contemplated that different lengths and differentnumbers of injection members 68 can be used to optimize a desiredtemperature distribution. Further still, different temperature zones atdifferent locations over the tissue contact surface area 22 of theexpandable element 18 can be provided as desired.

[0063]FIG. 14 is a sectional view of an exemplary interface region takenalong section 14-14 in FIG. 1. For exemplary purposes only, FIG. 14shows a body 12 configuration as shown in FIG. 6, however, it iscontemplated that other body 12 configurations can be provided. A filler80 forms a fluid fight seal between the inlet conduit 56 and theinjection members 68, thereby providing a path of fluid communicationfrom the inlet conduit 56 to the openings 76 and in turn, to theinterior volume 28 of the expandable element 18. Further, the filler 80is any suitable material having bonding properties, for example,silicone, rubber, flexible polymers, epoxies or other bondingcomponents. FIG. 14 shows two injection members 68, however, it iscontemplated that any quantity of injection members 68 can be provided.

[0064]FIG. 15 is a perspective view of a junction 74 of a deviceconstructed in accordance with the principles of the present invention.A junction 74 can be formed from the filler 80 described above, formedfrom a “plug” of material or other methods may be employed, for example,the junction 74 can be machined or injection molded.

[0065] A plurality of injection members 68 are attached and in fluidcommunication with the junction 74. In turn, junction 74 is attached toand in fluid communication with the inlet conduit of the body 12, asdiscussed below. FIG. 14 shows four injection members 68, however, it iscontemplated that any quantity of injection members 68 can be provided.

[0066]FIG. 16 is a sectional view of another exemplary interface regiontaken along section 14-14 in FIG. 1. Junction 74 is disposed at leastpartially within the inlet conduit 56 and is fixedly attached and influid communication therewith. The junction 74 is attached to the inletconduit 56 by methods known in the art. Additionally, outlet conduit 60is shown in partial sectional view. Both the injection members 68 andthe outlet conduit 60 are in fluid communication with the interiorvolume 28 of the expandable element 18. For exemplary purposes only,FIG. 16 depicts a body 12 configuration as shown in FIG. 7, however, itis anticipated that alternate configurations can be provided.

[0067]FIG. 17 is a cut-away, perspective view of an alternate bodyarrangement constructed in accordance with the principles of the presentinvention. FIG. 17 shows a plurality of injection members 68 disposedwithin outlet conduits 60 which are located inside a portion of theperiphery of the body wall 52 (some shown in cut-away). Further theinlet conduit 56 is provided in the center of the body 12.

[0068]FIG. 18 is a cut-away, perspective view of another alternate bodyarrangement constructed in accordance with the principles of the presentinvention. FIG. 18 shows a plurality of injection members 68 disposedwithin a plurality of inlet conduits 56. A centrally located outletconduit 60 is also provided.

[0069]FIG. 19 is a sectional view taken along section 19-19 in FIG. 5constructed in accordance with the principles of the present invention.FIG. 19 shows a expandable element arm 38 having an arm wall whichdefines the interior volume 28. Provided within the interior volume 28is an injection member 68 having an opening 76 which is in fluidcommunication with the interior volume 28. It is contemplated that allor some of the expandable element arms 40 shown in FIG. 5 can have aninjection member 68 provided therein. The attendant advantages of suchan arrangement are discussed with reference to other expandable elementconfigurations herein. For example, temperature control along theexpandable element arms 40 and selective deployment of individual armscan be provided.

[0070]FIG. 20 is a perspective view of an alternate embodiment of aninjection member arrangement constructed in accordance with theprinciples of the present invention. FIG. 20 shows an alternateinjection member arrangement having a unitary structure 84 whichincludes at least one injection tube arm 86. Further, unitary structure84 has an inlet port 88. The injection tube arm 86 defines a tip opening90. The unitary structure 84 is configured so that inlet port 88 isfixedly attached to inlet conduit 56 at the distal end 16 of the body12. The entire unitary structure 84 is enveloped by the expandableelement 18 (not shown). In practice, thermally conductive fluid isintroduced into the unitary structure 84 and then flows into theexpandable element 18 via tip opening 90. As such, the expandableelement 18 is “inflated” with thermally conductive fluid, which therebyaffects the temperature of the expandable element.

[0071]FIGS. 21, 22 and 23 are side, overhead and bottom viewsrespectively, each showing the unitary structure 84. While fourinjection tube arms 86 are shown, it is understood that otherarrangements having fewer or greater quantities of injection tube arms86 can be provided. The unitary structure 84 can be constructed fromflexible material by casting, extruding or other suitable means. Forexample, injection molding can be used.

[0072]FIG. 24 is a perspective view of an exemplary system constructedin accordance with the principles of the present invention. Anexpandable element 18 is in a bundled state attached to the distal end16 of the body 12. FIG. 24 shows inlet conduit 56 and outlet conduit 60in phantom lines. Inlet conduit 56 is in fluid communication with athermally-conductive fluid source 94 via body 12. Further, inlet conduit56 is in fluid communication with the interior volume 28 (not shown) ofthe expandable element 18. Further still, the outlet conduit 60 is influid communication with the interior volume 28 (not shown) of theexpandable element 18. The outlet conduit is in fluid communication withthe thermally-conductive fluid source 94 via body 12. Inlet conduit 56and outlet conduit 60 are in fluid communication with the interiorvolume 28 of the expandable element 18 and define a fluid circulationcircuit.

[0073] In practice, the expandable element 18 is inserted in its bundledstate 92 into the body of a subject to be treated. When the expandableelement 18 is positioned at a desired treatment region, fluid isintroduced into the expandable element 18 via the thermally-conductivefluid source 94—body 12 circuit, thereby “deploying” the expandableelement. When the expandable element is in its deployed state, the fluidcontinues to flow through the circuit and thereby thermally affects theexpandable element 18, which thereby thermally affects the tissuetreatment site.

[0074]FIG. 25 is a perspective view of the exemplary system of FIG. 24showing the expandable element 18 in a deployed state 98. For the sakeof simplicity, those elements described with respect to FIG. 24 are notagain described.

[0075] In practice, once the expandable element 18 is deployed, thethermally-transmissive fluid enters the interior volume 28 of theexpandable element 18 through inlet conduit 56 thereby thermallyaffecting the wall 26 of the expandable element 18 by convection. At orabout the same time, outlet conduit 60 excavates thethermal-transmissive fluid from the interior volume 28 of the expandableelement 18. In this manner, the thermally-transmissive fluid affects aspecific, controlled temperature to the wall 26 of the expandableelement 18. Additionally, the wall 26 of the expandable element 18 canbe fully or partially perfusive of fluid, to thereby allow fluid todirectly contact tissue for treatment purposes. In addition, amedicament or other treatment fluid can be administered in this manner.

[0076] It is contemplated that the expandable element 18 can be deployedby various methods, for example, by inflation with thethermally-transmissive fluid, by mechanical supports, by employing abuilt-in biased shape of the expandable element 18, or other methodsknown in the art.

[0077] Specific construction of exemplary embodiments is now discussedin more detail. Expandable element and shaft materials are varied toaccommodate specific applications. When used in an exemplaryapplication, such as epidurally in the skull, to control temperaturelocally in the brain, the materials are preferably soft and pliable, forexample composed of silicone polymer, soft pellethane (such aspellethane 80AE) or Pebax 42. Other applications may require theexpandable element to have separate characteristics such as moredurability or different compliant/non-compliant requirements. Thethermally-transmissive fluid can be saline or a refrigerant which iscooled by a thermoelectric cooler or a refrigerant fluid. It is notedthat cooled fluid can be used to chill cerebrospinal fluid.

[0078] Exemplary uses of the devices of the invention are now discussedin more detail. The above-described devices advantageously provide aphysician with a way to control the temperature of a localized region ofbrain tissue by infusing a chilled or heated thermally-transmissivefluid, such as saline, into the expandable element and allowingconvection to complete the thermal transfer between the localized braintissue and the expandable element. This is preferably accomplishedthrough a burr hole in the skull. The exemplary applicationadvantageously provides a chilled fluid in order to lower the localizedbrain temperature as a neuroprotective means in a cerebral ischemiacondition. Also it is contemplated that the above-described device canadditionally be used to cool localized regions of the brain in a braintrauma patient as a way to lower cerebral metabolic requirements andminimize brain edema. Furthermore, the device can also be used in anypost-operative trauma situation when the possibility of cerebral edemaexists and it is desired to be abated or minimized.

[0079] It is contemplated that the device described above can also beused in alternate procedures, for example, the device can be placedthrough the nose into the ethmoid sinus (neck skull bone) to coolcarotid blood as it courses through the cavernous sinus up to the brain.Further, the device can be placed adjacent the hypothalamus and a warmedfluid circulated through the device to raise the temperature perceivedby the hypothalamus, thereby triggering peripheral vasodilation andsystemic cooling.

[0080] Further, the above described device can be used in other parts ofthe body in instances where local tissue temperature needs to becontrolled or modulated. In such instances, thermal therapy may involveeither chilled or heated fluid inside the expandable element to achievethe desired result. For example, the device could be applied to organsprior to or post transplant (e.g. kidney) to minimize ischemia andswelling. Further, the device could use be used to minimize uterineirritability in a female subject that is at risk for premature delivery.

[0081] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. An expandable device for thermally affectingtissue, comprising: a fluid conduit having a longitudinal axis; and anexpandable element, the expandable element including: a wall defining aninner volume, the wall having a tissue contact region, the tissuecontact region being non-coaxial with the longitudinal axis of the fluidconduit, the tissue contact region being operable to have a firstcontact surface area and a second contact surface area, the secondcontact surface area being larger than the first contact surface area.2. The device according to claim 1, wherein the fluid conduit is aflexible catheter.
 3. The device according to claim 1, wherein theexpandable member is a balloon.
 4. The device according to claim 1,wherein the expandable element has a non-circular shape.
 5. The deviceaccording to claim 1, wherein the wall is arranged to define asubstantially circular shape.
 6. The device according to claim 1,wherein the wall is arranged to define a spider-like shape.
 7. Thedevice according to claim 1, wherein the fluid conduit is comprised of:an inlet conduit, the inlet conduit providing a path for thermallytransmissive fluid from the fluid source to the expandable member; andan outlet conduit, the outlet conduit providing a path for the thermallytransmissive fluid from the expandable member to the fluid source,wherein the fluid source, the fluid supply conduit and the expandableelement define a circulation circuit.
 8. The device according to claim1, further comprising a fluid distribution member provided within theinterior volume of the expandable member.
 9. The device according toclaim 8, wherein the fluid distribution member is a vane.
 10. The deviceaccording to claim 8, wherein the fluid distribution member is aninjection member, the injection member having an opening defining afluid communication path between the fluid conduit and the interiorvolume.
 11. The device according to claim 10, wherein a plurality ofinjection members each have a length different from at least one otherinjection member.
 12. The device according to claim 10, wherein aplurality of injection members each have a length equal to each otherinjection member.
 13. The device according to claim 1, wherein thetissue contact region is aligned substantially parallel to thelongitudinal axis of the fluid conduit.
 14. The device according toclaim 10, wherein the injection member is comprised of a plurality ofarms.
 15. The device according to claim 10, further comprising ajunction provided at an end portion of the fluid conduit, the junctionforming a fluid tight seal between the injection member and the fluidconduit.
 16. The device according to claim 15, wherein the junction is aresilient material.
 17. The device according to claim 1, furthercomprising an accessory conduit, the accessory conduit being incommunication with the inner volume of the expandable element.
 18. Thedevice according to claim 1, further comprising a temperature sensorconfigured to detect temperature of a tissue to be treated.
 19. Thedevice of claim 1, wherein the expandable member is comprised of aresilient material.
 20. The device of claim 1, wherein the wall iscomprised of a top and a bottom opposite the top, a height of theexpandable element being measured from the top of the expandable elementto the bottom of the expandable element, wherein the expandable elementhas a deployed diameter to height ratio of approximately 1-to-1 toapproximately 2-to-1, the deployed diameter being measured at a widestpart of the wall when the device is in a deployed state.
 21. Anexpandable element for thermally affecting tissue, comprising: a port,the port having a longitudinal axis; and a wall defining an innervolume, the wall having a tissue contact region, the tissue contactregion being non-coaxial with the longitudinal axis of the port, thetissue contact region being operable to have a first contact surfacearea and a second contact surface area, the second contact surface areabeing larger than the first contact surface area; the port being formedthrough the wall.
 22. The device according to claim 21, wherein theexpandable member is a balloon.
 23. The device according to claim 21,wherein the expandable element has a non-circular shape.
 24. The deviceaccording to claim 21, wherein the wall is configured to define asubstantially circular shape.
 25. The device according to claim 21,wherein the wall is configured to define a spider-like shape.
 26. Thedevice according to claim 21, further comprising a fluid distributionmember provided within the interior volume of the expandable member. 27.The device according to claim 26, wherein the fluid distribution memberis a vane.
 28. The device according to claim 26, wherein the fluiddistribution member is an injection member, the injection member havingan opening defining a fluid communication path between the fluid conduitand the inner volume.
 29. The device according to claim 28, wherein aplurality of injection members each have a length different from atleast one other injection member.
 30. The device according to claim 28,wherein a plurality of injection members each have a length equal toeach other injection member.
 31. The device according to claim 21,wherein the tissue contact region is aligned substantially parallel tothe longitudinal axis of the port.
 32. A method of using an expandableelement to affect a thermal energy change in tissue of a patent's body,comprising: creating an opening in the patient's body; inserting atleast a portion of the expandable element into the opening and into aregion between an outer barrier of the patent's body and the tissue, theexpandable element being in fluid communication with a fluid conduit,the expandable element having a tissue contact region, the tissuecontact region being non-coaxial with a longitudinal axis of the fluidconduit, the tissue contact region being operable to have a firstcontact surface area and a second contact surface area, the secondcontact surface area being larger than the first contact surface area;operating the tissue contact region to the second contact surface area;and infusing a thermally transmissive fluid into the expandable element.